www/py-django32: unbreak build for HTML docs (+)

Same fix as 64b2298a6d98dfcc467c328b18293f558fa92c59 for Django40.

Django require at least sphinx 4.5.0 to generate offline HTML docs.
Set version check for dependency.

Another issue is gmake-style construction in docs/Makefile.
Force gmake usage for HTMLDOCS option to resolve build issue.

Pointyhat to: wen (for skipped dependencies chech)
Approved by: portmgr blanket (fix build)
MFH: 2022Q3